The open impeller applicable to liquid rocket pumps is a new technology compared to the conventional closed impeller widely used in existing liquid rocket engines. This paper describes the application of three-dimensional and unsteady Reynolds-averaged Navier-Stokes simulations to investigate the detailed flow field in a liquid rocket hydrogen pump with an open impeller. In order to investigate the influence of the compressibility of hydrogen, both compressible and incompressible URANS simulations were performed for comparison with the LE-X hydrogen pump test. First, the computed results were validated relative to the experimental results obtained in the pump test. Second, the detailed flow field was investigated by comparing the compressible and incompressible URANS results. The computed results agreed well with the experimental results, and revealed several key features in the open impeller.

Cavitating flow around a Clark Y-11.7% hydrofoil in a water tunnel is experimentally studied in order to understand the relationship between cavity patterns and lift and drag characteristics under some boundary layer conditions. The experiments are carried out under various conditions about angles of attack and the amount of dissolved air. Oil film method is conducted in order to investigate the detail of boundary layer on the hydrofoil at the various angles of attack. At the angles of attack of 2° and 20°, dissolved air content has some impact on both cavitation behavior and cavitation performance of hydrofoil, but it affects only cavitation behavior at the angle of attack of 8°. Also, lift and drag force oscillations are measured and they correspond to that of the cavity growth and disappearance at the angle of attack of 20°.

Our aim is to understand the air entrainment into a suction pipe inside a suction sump in the vertical-wet-pit-pump configuration. This suction-sump flow accompanying the air entrainment often appears in various industrial and environmental problems, however is usually complicated owing to both their unsteadiness with poor periodicity and their fully-three-dimensionality. In the present study, we investigate the influences of governing parameters upon the occurrence-time ratio γ of the air entrainment using a bubble sensor.

A straight-bladed vertical axis turbine for wave energy conversion has been proposed in order to develop a novel air turbine suitable for an oscillating water column based wave energy plant. This study aims at investigating the effect of guide vane position on the performance of a straight-bladed vertical axis turbine. The experimental study was performed by using a wind tunnel. The rotor comprises four straight blades with a profile of NACA0018, chord length of 80.5 mm, pitch radius of R=230 mm, and blade width of 490 mm. The guide vane has a profile of a circular arc and a chord length of l=87 mm. The gap between the rotor blade and the guide vane G is altered for investigating the effect of the guide vane position G / R. The experimental results indicate that the guide vane position G / R suitable for the proposed turbine is obtained in the case of G / R =0.11.

Hydroelectric power generation is a highly stable renewable energy power, and it is necessary to optimize hydro turbine design to meet each specification. In order to enhance hydraulic performance, a multi-objective design optimization was carried out by using Computational Fluid Dynamics (CFD). To increase the degrees of freedom of the design, blade shape of runner was defined by NURBS curve. The optimization algorithm employs Particle Swarm Optimization (PSO). As a result, the pareto solutions exceeding the conventional design were obtained, and also the correlations between the objectives were evaluated.

There are many kinds of pumps for fluid foods depending on the characteristics of the fluid, i.e. a sanitary pump made from the stainless steel, a screw pump and so on. The purpose of this research is establishment of the pump design method for the low viscous fluid food based on the internal flow condition. In this research, the centrifugal pump having small number of the blade is used to decrease the shear loss and keep wide flow passage. Moreover, a open impeller is adopted in this centrifugal pump in consideration of the manufacturing precision and simple maintenance of the pump. Four impellers having the different blade outlet angles are prepared and the performance test is conducted using the experimental apparatus. The internal flow condition of each type of the impeller near the hub is clarified by the numerical analysis and the suitable impeller for low viscous fluid food is considered based on the experimental and numerical analysis results.